如圖所示,各用4N的水平力沿相反的方向拉彈簧測(cè)力計(jì)的兩端(彈簧測(cè)力計(jì)自重不計(jì)),則下列說(shuō)法中正確的是()
A.彈簧測(cè)力計(jì)的示數(shù)為4N,彈簧測(cè)力計(jì)受的合力為4N
B.彈簧測(cè)力計(jì)的示數(shù)為0N,彈簧測(cè)力計(jì)受的合力為0N
C.彈簧測(cè)力計(jì)的示數(shù)為8N,彈簧測(cè)力計(jì)受的合力為0N
D.彈簧測(cè)力計(jì)的示數(shù)為4N,彈簧測(cè)力計(jì)受的合力為0N